Mounting evidence of association of various human kidney diseases with viral infections encourages a thorough and systematic examination of diseased renal tissues for evidence of viral roles in pathogenesis. Thus, tissues obtained from renal biopsy performed for diagnostic purposes in patients with various renal diseases and from surgically removed end-stage kidneys from renal transplantation candidates undergoing hemodialysis will be investigated for evidence of specific viral pathogenetic activity. Tissues will be cultivated in vitro on collagen substrates and co-cultivated with human cells in an effort to unmask, isolate, and subsequently identify residual viruses. In nephrectomy specimens dissociation of infectious particles from immune complexes will be attempted by pH manipulations, and donor patient buffy coat cells will be added to cultures of these specimens in attempts to demonstrate possible auto-immune mechanisms of tissue damage. Effects of medium variations and ultraviolet irradiation on latent virus unmasking will also be investigated. Simultaneously, sequential examination for specific viral antigen localization in frozen sections by fluorescent antibody techniques will be undertaken for Coxsackieviruses types B 1-6 and A-4, adenoviruses, echovirus type 9, herpes simplex, influenza virus types A and B, parainfluenza viruses types 1-4, and serum hepatitis virus. Tissues will ultimately be glutaraldehyde-fixed for future electron microscopy. Specific antibodies to any viruses so identified will be quantitated in serial serum specimens from donor patients to ascertain patterns of specific immune responses and to strengthen evidence for viral etiology of the disease in question. Finally, attempts will be made to correlate functional and anatomic abnormalities with activities of any viruses so isolated.